螺旋手性SWCNT的尺寸对赖氨酸分子手性转变反应的限域影响

发布时间：2018-10-23 07:32

【摘要】：采用量子力学与分子力学组合的ONIOM方法,研究了两种构象的赖氨酸分子限域在螺旋手性单壁碳纳米管内的手性转变机理.结构分析表明:纳米管管径越小,限域在其中的赖氨酸分子骨架形变越明显,手性碳上的氢原子与氨基上氮的氮原子距离越小.势能面计算表明,两种构象的赖氨酸分子限域在SWCNT(6,4)时,旋光异构反应决速步的吉布斯自由能垒分别是194.72和170.08kJ·mol~(-1),分别由质子从手性碳向氨基氮和质子从手性碳向氨基氮与氨基上的质子向羰基氧双质子协同迁移的过渡态产生的.与裸反应的此通道决速步能垒252.6kJ·mol~(-1)相比较有显著降低.两种构象的赖氨酸分子限域在SWCNT(6,4)内旋光异构反应的表观能垒分别是160.00和178.59kJ·mol~(-1).他们限域在SWCNT(7,4)内时,旋光异构反应决速步的能垒分别是238.28和217.18kJ·mol~(-1);限域在SWCNT(8,4)内时,旋光异构反应决速步的能垒分别是253.00和250.11kJ·mol~(-1).结果表明:螺旋手性单壁碳纳米管的孔径越小,对赖氨酸分子手性转变反应的限域催化作用越好;限域在SWCNT(6,4)内的赖氨酸分子构象1更容易旋光异构.
[Abstract]:The chiral transition mechanism of two conformational lysine molecular limiting regions in spiral chiral single-walled carbon nanotubes was studied by using ONIOM method combined with quantum mechanics and molecular mechanics. The structure analysis shows that the smaller the diameter of nanotubes, the more apparent the deformation of lysine molecular skeleton in the limiting region, and the smaller the distance between the hydrogen atom on the chiral carbon and the nitrogen atom on the amino group. The potential energy surface calculation shows that the Lysine molecular limiting region of the two conformations is at SWCNT _ (6 ~ (4). The Gibbs free energy barrier of the reaction is 194.72 and 170.08kJ mol~ (-1), respectively, resulting from the transition of protons from chiral carbon to amino nitrogen and from protons on amino groups to carbonyl oxygen diprotons. Compared with the bare reaction, the 252.6kJ mol~ (-1) of the fast step barrier in this channel is significantly reduced. The apparent energy barriers of the two conformational Lysine molecular limiter reactions in SWCNT (6 ~ 4) are 160.00 and 178.59kJ mol~ (-1), respectively. The energy barriers of the fast step of optically isomerism reaction are 238.28 and 217.18kJ mol~ (-1), respectively, and the energy barriers of the fast step of the reaction of optically isomerism reaction are 253.00 and 250.11kJ mol~ (-1), respectively, when the limiting region is in SWCNT (7 ~ 4), and the energy barrier of the fast step of the reaction is 253.00 and 250.11kJ mol~ (-1), respectively, when the limiting region is within SWCNT (8 ~ (4). The results show that the smaller the pore size of the helical chiral carbon nanotubes, the better the limited catalytic effect on the chiral transition reaction of lysine molecules, and the easier the optical rotation isomerization of lysine molecular conformation 1 in SWCNT (6N4).
【作者单位】：白城师范学院物理学院;
【基金】：吉林省科技发展计划自然科学基金(20130101308JC) 吉林省高等学校大学生创新项目(2016002)
【分类号】：O629.71

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